Аннотация:The analysis of an image captured under arbitrary conditions requires preliminary normalization: a conversion to such a form as if the image was captured under normal, i.e. convenient for the further analysis, conditions. This paper presents a review of modern methods, accuracy criteria, and applications of various normalization approaches. The main stages of the problem development are described. For the first time, the two most important special cases of normalization, conventionally considered independently in the literature, are examined in a unified way. The first special case covers only geometric issues, and the second one is concerned with color aspects exclusively. We demonstrate that the normalization procedure fundamentally involves two- and three-dimensional projective transformations within a general analytical framework, without regard to its color and geometric interpretation for practical problems. This implies the advantage of the suggested unified approach.